钢渣基固废掺和料抗压强度与活性分析

Analysis of Compressive Strength and Activity of Steel Slag Based Solid Waste Admixture

为促进固废的资源化利用、解决钢渣活性指数不高等问题,以钢渣、矿渣、陶瓷粉(以下统称为SGC)为掺和料替代部分水泥制备复合胶凝材料。通过力学性能测试、扫描电镜、差热-热重(DTA-TG)和X射线衍射(XRD)分析,探索SGC掺和料体系在不同配比及掺量下对胶砂强度及水化产物的影响,并分析复合胶凝材料的水化机理,确定最佳活化方案。结果表明,单掺钢渣表现出较低的活性;钢渣-矿渣双掺组表现优于钢渣-陶瓷粉。在三掺体系中,水化早期钢渣和矿渣水化生成Ca(OH)_(2)和少量的水化硅酸钙(C-S-H)、水化铝酸钙(C-A-H)胶凝,提供早期强度,活性SiO_(2)和Al_(2)O_(3)与Ca(OH)_(2)发生二次水化反应生成大量C-S-H、C-A-H凝胶等水化产物。且三掺体系部分未发生反应的颗粒相互填充,因此SGC三元掺和料体系中存在耦合协同作用,共同促进体系强度增加,具备制备掺和料潜能。其中,钢渣、矿渣、陶瓷粉质量比为2∶1∶1,并以30%等质量替代水泥时,胶砂抗压强度最高,28 d抗压强度为45.6 MPa,活性指数达到93.08%。

In order to promote the resource utilization of solid waste and solve the problems of low activity index of steel slag,steel slag,slag and ceramic powder(SGC)were used as admixtures to replace part of the cement to prepare composite cementitious materials.Through mechanical property testing,scanning electron microscopy,DTA-TG and XRD analysis,the effects of SGC admixture systems on the strength and hydration products of mortar under different ratios and dosages were explored,and the hydration mechanism of composite cementitious materials was analyzed to find the best activation scheme.The results showed that the single doped steel slag exhibited low activity.The performance of steel slaGslag double doping group was better than that of steel slaGceramic powder.In the three-doping system,the steel slag and slag in the early stage of hydration produced Ca(OH)_(2) and a small amount of C-S-H and C-A-H gel,which provided early strength,and the secondary hydration reaction of active SiO_(2) and Al_(2)O_(3) with Ca(OH)_(2) produced a large number of hydration products such as C-S-H and C-A-H gel.Moreover,the unreacted particles of the three-doping system were filled with each other,so there was a coupling synergy in the SGC ternary admixture system,which jointly promoted the increase of the strength of the system and had the potential to prepare admixture.When the mix ratio of steel slag,slag and ceramic powder was 2∶1∶1,and 3%SGC was used to instead of cement,the compressive strength of the mortar was the highest,which was 45.6 MPa in 28 d,and its activity index reached 93.08%.